Core Knowledge

Nutrition

Contents

All About Minerals

The Nutrition TeamMay 7, 2009

Overview

Approximately 21 minerals are essential for life, and some—potassium, sodium and iron—are of particular concern to athletes. Minerals are also more likely to have an immediate effect on the health and performance of an athlete than vitamins. A well-balanced diet is the key to getting enough minerals.

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Potassium

Potassium is an electrolyte needed for maintaining the body's balance of fluids, for proper kidney functioning and for conducting electricity in the body. The estimated minimum daily requirement for potassium among athletes over the age of 18 is 2,000 milligrams (but it may vary between athletes). Those who weigh under 189 pounds may need less, and those who take in more than 2,000 calories a day may need more. You can replace potassium lost through sweat by drinking a glass of orange juice. Other sources of potassium are fruits (especially bananas) and vegetables. Potassium supplements aren't needed for the average person. Too much potassium can cause irregular heart rhythms.

Sodium, Sodium Chloride

Sodium is an electrolyte that can be lost through perspiration. A sodium deficiency is more likely to affect endurance athletes than others. One gram of sodium can be lost with two pounds of body weight through sweat, but it can be replaced by just a half teaspoon of salt. A well-balanced diet should provide more than enough sodium chloride (salt).

Calcium

Calcium has a direct effect on bone density and bone strength. It is important in the process of muscle contraction, and a calcium deficiency can lead to muscle cramps, as well as stress fractures. Athletes, particularly young ones, frequently consume less calcium then they should because they drink fewer dairy products than older athletes. Milk tends to be replaced by soft drinks. Aim between 1,000 and 1,800 milligrams of calcium per day to attain peak bone mass.

Getting enough calcium may be a particular problem for those who do not eat dairy products. Vegetarians may require less calcium than others because they absorb and retain more calcium from foods than non-vegetarians. Calcium obtained from animal sources is not readily absorbed. Good sources of calcium include:

fish with bones

broccoli

kale

collard greens

orange juice

fortified soy milk

fortified tofu and fortified cereals (Cheerios, Total, Special K).

For individuals who take calcium supplements, calcium carbonate and calcium citrate are absorbed by the body more efficiently than other forms. Do not take calcium and iron supplements simultaneously. Calcium can block iron absorption.

Iron

Iron is needed to transport oxygen to muscles and other tissues. It is absolutely essential for aerobic endurance performance, and iron depletion is the first and most common type of mineral deficiency among athletes. Vegetarians must make sure they get enough because iron from plant sources is not as easily absorbed as it's from animal products.The best sources of iron are:

beef

veal

pork

chicken

fish

shellfish

Other sources include iron-fortified cereals, spinach, raisins, apricots, baked potatoes, molasses, clam chowder, lentils and canned tuna. The absorption of iron is even more efficient when eaten with a glass of orange juice or sliced strawberries.

Zinc

Zinc is needed for healing and immunity, and it is involved in energy metabolism. If you are getting adequate servings of protein from meat, you are probably getting enough zinc. Between 14 and 20 milligrams of zinc is commonly added to vitamin/mineral supplements, but larger amounts (50 to 100 milligrams per day) consumed over an extended period of time could have negative affects on copper and iron status. Not getting enough zinc could negatively affect training, cause an increase in the risk of injury and delay the recovery process.

Chromium

Chromium may help burn fat and build muscle, but these claims have not been proven. Sports nutritionists are concerned about the potential dangers of chromium supplements taken by exercisers and athletes. Excess chromium may contribute to anemia, which hurts athletic performance.